Official Statistics of Finland (OSF):
Changes in marital status [e-publication].ISSN=1797-643X. 2013,
Appendix figure 1. Average age of women by first marriage and first live birth 1982–2013
. Helsinki: Statistics Finland [referred: 14.12.2017].Access method: http://www.stat.fi/til/ssaaty/2013/ssaaty_2013_2014-04-17_kuv_001_en.html